Recently I've integrated a Java proxy server and Image to ZX Spec to allow you to surf the web seeing every image as would be displayed on a ZX Spectrum.
Of course the youtube video being low resolution doesn't really help, but look at about 2 minutes in to see the difference when I disable the proxy.
I'll be releasing the proxy patches and a modified version of Image to ZX Spec that will allow you to do this with your own browser in a few days (fun for parties maybe?!!). If I get time I'll also add conversion of the font so the text on the pages even looks like that on a Spectrum.
If you came here looking for a real way of getting your old Spectrum on the net you should have a look at Spectranet.